This invention relates to bis(aminostyryl)benzene compounds which are suitable for use as an organic luminescent material capable of developing a desired luminescent color and to synthetic intermediates thereof. The invention also relates to a process for preparing such compounds and intermediates as mentioned above.
As a candidate for flat panel displays which make use of spontaneous light, have a high response speed and have no dependence on an angle of field, attention has been recently paid to an organic electroluminescent device (EL device), and an increasing interest has been taken in organic luminescent materials for the EL device. The first advantage of the organic luminescent material resides in that the optical properties of the material can be controlled, to an extent, depending on the molecular design, so that it is possible to realize a full color organic luminescent device wherein three primary color luminescences of red, blue and green can be all created by use of the respective organic luminescent materials.
The bis(aminostyryl)benzene compound of the following general formula (A) is able to develop blue to red strong luminescences in a visible region depending on the type of introduced substituent wherein Ar represents an aryl group which may have a substituent, Ra and Rb, respectively, represent a hydrogen atom, a saturated or unsaturated hydrocarbon group, an aryl group which may have a substituent, a cyano group, a halogen atom, a nitro group or an alkoxy group and may be the same or different. Hence, this compound is utilizable not only as a material for an organic electroluminescent device, but also in various fields. These materials are sublimable in nature, with the attendant advantage that they can be formed as a uniform amorphous film according to a process such as vacuum deposition. Nowadays, although optical properties of a material can be predicted to some extent by calculation of its molecular orbital, it is as a matter of course that a technique of preparing a required material in a high efficiency is most important from the industrial standpoint.
Up to now, a large number of compounds including those of the above general formula (A) have been prepared for use as an organic luminescent material. The fluorescence or luminescence of these materials mostly covers blue to green colors, and only a few of materials which develop yellow to red luminescence has been reported [Technical Investigation Report of The Association of Electric Information Communication, Organic Electronics, 17, 7 (1992), Inorganic and Organic Electroluminescence 96 Berlin, 101(1996) and the like]. In addition, there has never been established any process of preparing such materials in a high efficiency.